farmall m carb freezing up

We just recently put back together our 1951 m and had the carb sent out to Denny"s in Ohio. Got it on and running and it runs great...for a minute or two. The carb turns ice cold on the top end and freezes up, choking out the tractor (85 plus degrees today!). I removed the air tube intake to the carb and same problem. Air intake is working perfectly. Anybody else have this problem? Any advice here?

Just curious. What's Denny getting for a rebuild now? Does he offer a warrantee?

Gordo

This time of year (humidity) mine also gets condensation and ice on the outside for the first couple of minutes or so. Normally, I am not aware of it from the driver's seat. On very rare occasions it will stumble and miss a time or two, but I just "drive through it"; then it continues to warm on up and runs fine thereafter.
mike

Try re-adjusting the carburetor. This may get rid of your problem. Do you have a lot of humidity where you are located?

Carb adjustment: idle air screw is set at 1½ turn out to start with; high speed mixture screw is 2½ or 3 turns out.
With the engine warm & running at wide open throttle (WOT), turn high speed mixture screw (on the bottom facing down to the rear) in until the engine begins to starve for fuel. Then turn the screw out until the engine begins to blubber. Now find the "sweet spot" in between the two settings. If you are working the engine (plowing, etc.), then the high speed screw needs to be turned out ½ turn or more beyond the "sweet spot" to be sure the engine isn"t starving for fuel and can develop its rated power.
The same procedure should be followed for idle mixture. On the "H"& “M” carb, the idle mixture screw (faces to the front just below the idle stop screw) is an air adjusting screw so turning in will richen the mixture and out will lean the mixture.
Now set the idle stop screw (located where the governor shaft tube attaches to the carb) to adjust the low speed RPM.
Repeat the carburetor adjustment procedure again to make sure “all is well”.

Guess what?? If it didn't do that you would be in trouble or in other words that is normal and just the way thing work. Let it sit and warm up some and all will be well.

I have no personal experiences with Dennys but I have heard a lot more negative comments about them than positve

A carb isn't that hard to rebuild and rebuild kits can be had for under $30. Before rebuilding one I like to soak them in a bucket of carb cleaner for a couple days. I use the small buckets of carb cleaner you can get ar your local automotive store that comes with a basket for small parts. Make sure you get all the passages cleaned out after soaking.

If you have a gas manifold there should be a couple of small drain holes in the bottom of the exhaust portion of the manifold in front of the carburetor. Making sure sure those holes are open may help a little as they will blow a small amount of exhaust down by the carburetor.

Thanks for all the info. I'll try the re-adjustment and this past week has been extremely humid...I assume the moisture in the air drawn into the carb freezes up as the fuel atomizes. Hopefully lower humidity will help. It does have a gas manifold and I'll check the 'holes' another reply mentioned. Thanks again for all the info. Denny's is def. not the best way to go for a rebuild. This carb was completely gummed up as the tractor had sat for 10 years before we bought it. Denny's charged $255 for a rebuild...semi-mod to give a bit more power. I would not reccommend them! I had to disassemble the carb myself when I received it as the top end was jam packed with sand blasting compound and gunk they forgot to remove. The advertise that every carb is tested prior to leaving....obvioulsy this one was not tested!

I can sell a complete, rebuilt M carburetor for $250 and allow you $50 for your core. Modifying for more power is a worthless joke unless the engine is also modified, and then the carb needs to be modified to MATCH the engine. Otherwise you are just shooting in the dark.

When my M starts freezing up I add a couple cans of heet. Usually helps. Bernie Steffen

I recently had that problem with my F400. I removed an inline filter (redundant), blew out the lines & "vacuumed" out the gas tank. I've put about 3 hrs on it since I overhauled the rotten electrical system & cleaned the lines & tank. Haven't had a problem, yet. I still have a heater plate, on order from the Depot, in case the problem happens to come back & the previous does not work. If anything, I'll have another NOS part for my collection. :^) - Mike

I got a rebuilt carb from Rustyfarmall last year for my H and it works perfect!